Stretch yarn made of cotton and cotton type materials and process of producing the same



United States Patent 3,369,281 STRETCH YARN MADE OF QUTTON AND COT- TON TYPE MATERIALS AND PROCESS OF PRODUCHNG THE SAME Georg Edlich, Lorracli, Baden, Germany, assignor to Schipat AG, Zug, Switzerland, a corporation of Switzerland N0 Drawing. Filed Oct. 1, 1965, Ser. No. 492,281 Claims priority, application Germany, Oct. 15, 1964, E 27,959 8 Claims. (Cl. 2876) This invention relates to improvement in the qualities of so-called stretch yarn made of cotton and similar fibrous material.

Stretch yarn is generally understood by those skilled in the extile art to be a yarn material having permanentelastic qualities which are not lost through subsequent after-treatment, such as, dyeing, washing, or the like, even without the application of tension. In the contrary, stretch yarns, even when processed provide garments which cling to the body, following its movements while retaining their original shape even under prolonged tensional and compressive stresses. Such stretch yarn commonly consists of synthetic fibers but is also known to be made of cotton. Such a stretch yarn made of cotton is prepared by first treating highly overtwisted yarns or twists under tension with humid heat, such as steam, and thereafter dyeing them again under tension.

It is also known to mercerize cotton yarns and fabrics, that is to treat them with aqueous alkaline solutions to shrink them and provide non-elastic crepe goods. Most recently there is also a process of mercerization which operates without tension and provides all-cotton stretch socks with qualities of clinging and relaxation which, however, do not equal those of texturized synthetic goods. This process consists in treating extremely loosely knitted socks without tension with rather concentrated sodium hydroxide lye, viz, -30%, at temperatures ranging between 26 and 91 C. It has been found that higher yarn twists, higher caustic concentrations and lower temperatures result in a reduction of the softness in hand. The yarns which were used had a normal twist and, in order to test yarns having an extreme twist (so twisted to avoid twisting of the goods during knitting), yarns were used which consisted. of two yarns highly twisted in the same sense or direction and twisted together in the reverse sense.

According to the invention it has been unexpectedly discovered that the foregoing principle of slack mercerization also provides the desired stretch effect with extremely low lye concentrations it the yarn to be treated is given a specific twist structure. Such structure principally consists in the doubling of at least two single yarns having the same degree of twist but in opposite directions (8 and Z twist), the doubling being in a greater measure than the twist of the single yarns.

Twists structured in this manner wherein the single yarn which untwists during the doubling embraces the other single yarn which overtwists during the doubling are known per se and for the most part consist of combinations of synthetic and natural yarns. Such twists are given some elastic stretchability by the overtwisted yarn component and softness in hand or velvet sheen by the embracing yarn. However, these known twists and textile goods made thereof have not been heretofore aftertreated according to the principle of the slack mercerization.

It is accordingly a primary object of the present invention to provide an improved stretch yarn made of cotton and cotton type materials and a process of producing the same.

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The present invention primarily comprises a cotton stretch yarn characterized in that it consists of at least two single yarns double with 136-166 turns per meter, each single yarn having the same degree of individual twist but of opposite direction or sense. The individual twist is weaker than the degree of double twist, such as 106-122 turns per meter, and the yarn is mercerized in hot 0.05 sodium hydroxide lye. The invention also comprises textile goods made of such stretch yarn.

The invention also comprises a process of producing such a cotton stretch yarn, such process being characterized in that at least two single yarns each being twisted with the same 1 06122 turns per meter but in opposite direction or sense with respect to each other are doubled with a twist measure of 136466 turns per meter, said measure being higher than that of the single yarn twists. The produced twist is mercerized in a hot about 0.05% caustic lye comprising a surfactant and afterwards is dried. Such mercerization may be given the non-fabricated twist as such but is preferably given the textile goods, e.g. the knitted or woven fabric. In both cases the treatment is performed with the twist in a non-tensioned state.

The surfactant, e.g. a conventional fat sulfonate, pr0- motes the diffusion of the weak lye especially into the overtwisted core yarn whereby a cross-swelling of the fibers and a corresponding longitudinal shrinking of the fabric is caused and fixed by the subsequent drying. The finished yarn and the textile goods produced therefrom have a high elastic elongation of 3040'% together with softness in hand and voluminous or bulky appearance.

As used herein the term caustic lye comprises all substances which react in a mercerizing manner on cotton, viz, causing a shrinking of its fibers. In the interest of economy and easy availability a commercially available sodium hydroxide lye of about 41.65% NaOH contents is used and applied in a concentration of 0.1%. As used herein the term cotton comprises cotton as such as well as all synthetic and natural substances which by reaction with weak alkaline solutions undergo a swelling which is stable even on subsequent washing or other finishing processes of the fiber substance of the threads,

such swelling being accompanied by a longitudinal shrinkage of the fibers. Such substances are known to those skilled in the mercerization art. Cotton per se and such cotton type materials are referred to collectively as cotton type materials in the claims herein. As used herein the term hot (lye) used for characterizing the invention comprises the area of temperature adjacent to the boiling point of the lye and is inversely reciprocally related to the duration of treatment in the manner known for chemical reactions. According to experience a one hour treatment with a 0.1% sodium hydroxide lye at about provides for the desired stretch yarn effect.

From the preceding it is evident that the invention.

consists of a combination ofon the one hand-a mechanical treatment (twisting) and-on the other hand-a chemical treatment (mercerization), both treatments being individually specific and harmonized with one another. In comparison with known methods there is no use of any twist or rippling. By the omission of any fixation whatsoever by synthetic resin and by the use of extremely weak lye concentrations essential savings in material costs are achieved. Furthermore, operation with such weak lyes eliminates the serious problem of accident prevention, otherwise encountered with the use of lyes, and effects a reduction of operational costs by eliminating the otherwise necessary washing of the final fabric to remove the lye.

Through the invention there is provided the substantial advantage that both the stretch yarn, as such, and

the textile goods produced therefrom, retain the natural qualities of the starting material e.g. cotton, such as heat retention, air permeability, ability to take up moisture, resistance to abrasion, and softness of fibers, and the final textile goods, especially as a shaped garment, have a permanent stretchability of 3040% as a knitted or woven product, and additionally are of permanent shape and resistant to creasing.

The following examples are intended as illustrative only, it being understood that the invention is not restricted thereto, it being evident that the invention may be realized in a variety of other ways within the scope of the invention and appended claims.

EXAMPLE 1 Width of the hose, mm 500 580 Weight per square meter, g 220 150 Cross elongation, percent 49 40 Longitudinal elongation, percent 131 115 EXAMPLE 2 1 :1 knitted fabric (rechts-and-rechts-fabric with alternating rechts-and-links-wales) produced on a 15-inch circular machine provided with 18 needles per inch; adjustment=90 mm./ 100 links (measured as in Example 1).

Fabric A made of stretch Ne 70/2 cotton yarn (according to the invention). 7

Fabric B made of normal Ne 35/1 cotton yarn.

Values of the fabrics relaxed as in Example 1:

Width of the hose, mm 420 420 Weight per square meter, g 178 142 Cross elongation, percent 31 17 Longitudinal elongation, percent 136 175 The higher value of longitudinal elongation of B is caused 'by the lower adjustment and mostly consists of permanent undesired elongation.

The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

What is claimed and desired to be secured by United States Letters Patent is:

1. A process of producing a stretch yarn of a mercerized cotton type material, comprising the steps of forming at least two individual yarns each having substantially the same twist of 106122 turns per meter but of opposite sense with respect to one another, twisting said individual yarns together with a twist of 136-166 turns per meter which is higher than that of the individual yarns, mercerizing the produced twist in a hot caustic lye of about 0.05% comprising a surfactant, and drying.

2. A process as claimed in claim 1, wherein the caustic lye comprises a 0.01% sodium hydroxide lye having a temperature of about C.

3. A process of producing a textile fabric of mercerized cotton stretch yarn, comprising the steps of forming at leasttwo individual yarns each having the same twist of 106122 turns per meter but of opposite sense with respect to one another, twisting said individual yarns together with a twist of 136166 turns per meter whcih is higher than that of the individual yarns, forming a body of links from the produced twist, mercerizing the produced body of links in a hot caustic lye of about 0.05% comprising a surfactant, and drying the body of links.

4. A process as claimed in claim 3, wherein the canstic lye comprises a 0.01% sodium hydroxide lye having a temperature of about 85 C.

5. A process as claimed in claim 4 including the step of forming said fabric into a shaped garment.

6. A process as claimed in claim 3 including the step of forming said fabric into a shaped garment.

7. A stretch yarn made according to the process of claim 1.

8. A fabric made according to the process of claim 3.

References Cited UNITED STATES PATENTS 8,303 8/1851 Mercer. 1,885,019 10/1932 Theis 2876 2,153,963 4/1939 Lejeune et al 2876 XR 2,153,964 4/1939 Lejeune 2876 XR 3,127,732 4/1964 Brown et al 57164 3,132,497 5/1964 Garrou 66202 3,145,132 8/1964 Seltzer 28-76 XR 3,287,788 11/1966 Goodbar et a1. 2876 3,299,486 1/1967 Meyers et a1 2876 FRANK I. COHEN, Primary Examiner.

J. PETRAKES, Examiner, 

3. A PROCESS OF PRODUCING A TEXTILE FABRIC OF MERCERIZED COTTON STRETCH YARN, COMPRISING THE STEPS OF FORMING AT LEAST TWO INDIVIDUAL YARNS EACH HAVING THE SAME TWIST OF 106-122 TURNS PER METER BUT OF OPPOSITE SENSE WITH RESPECT TO ONE ANOTHER, TWISTING SAID INDIVIDUAL YARNS TOGETHER WITH A TWIST OF 1336-166 TURNS PER METER WHICH IS HIGHER THAN THAT OF THE INDIVIDUAL YARNS, FORMING A BODY OF LINKS FROM THE PRODUCED TWIST, MERCERIZING THE PRODUCED BODY OF LINKS IN A HOT CAUSTIC LYE OF ABOUT 0.05% COMPRISING A SURFACTANT, AND DRYING THE BODY OF LINKS. 